Abstract: Embodiments related to systems and methods for controlling the relative amounts of rotation and heave motions applied to a seat by an active seat suspension system are described.

Abstract: Disclosed herein are hydraulic actuators and methods for the operation of actuators having variable relative pressure ratios. Further disclosed are methods for designing and/or operating a hydraulic actuator such that the actuator exhibits a variable relative pressure ratio. In certain embodiments, the relative pressure ratio of the hydraulic actuator may be dependent on one or more characteristics (such as, for example, frequency or rate of change) of an oscillating input to the hydraulic actuator.

Abstract: Presented herein are systems and methods for attenuating flow ripple generated by a hydraulic pump. In certain aspects, a method and system for operating a hydraulic positive displacement pump according to a stabilized command profile are disclosed, such that flow ripple generated by operation of the pump according to the stabilized command profile is attenuated as compared to operation of the pump according to a corresponding nominal command profile. In other aspects, a pressure-balanced active buffer is disclosed that allow for at least partially cancelling flow ripple in a hydraulic circuit comprising a pump. In another aspect, a method for generating ripple maps for a pump is disclosed. Such ripple maps may be used, for example, to determine the stabilized command profile used to operate the pump, or may be used by the pressure-balanced active buffer to counteract ripple in the hydraulic circuit.

Abstract: Hydraulic systems and methods for reducing the propagation of flow and/or pressure fluctuations within a hydraulic system with a differential buffer are described. A differential buffer may include a first internal volume, a second internal volume, and a barrier separating at least a portion of the first internal volume and at least a portion of the second internal volume. The barrier may move to mitigate pressure and/or flow fluctuations in the first internal volume and the second internal volume by passive destructive interference.

Abstract: Hydraulic systems and methods for reducing the propagation of flow and/or pressure pulsations within a hydraulic system are described. In one embodiment, a hydraulic system may include a hydraulic device and a differential buffer fluidly connected to the hydraulic device. The differential buffer may include a piston that is exposed to pressure pulsations that propagate along separate flow paths and that are at least partially out of phase with one another. Corresponding displacement of the piston due to the out of phase pulsations may at least partially mitigate propagation of the pulsations within the hydraulic system downstream from the differential buffer.

Abstract: Active suspension systems including actuators with combinations of accumulators and flow restrictions, as well as their methods of operation, are described. In some embodiments, methods and constructions for mitigating pump ripple and/or resonances between different hydraulic components are also described.

Abstract: An active suspension system for a sprung mass that is supported and movable relative to an unsprung mass. The active suspension system has a suspension that comprises an electromagnetic actuator that is adapted to produce an arbitrary force on the sprung mass that is independent of the position, velocity and acceleration of the sprung mass, a control system that provides control signals that cause the suspension to exert force on the sprung mass, to control the position of the sprung mass relative to the unsprung mass, wherein the control system implements a control algorithm with one or more constants, and a user interface that is operable to cause a change of one or more of the control algorithm constants so as to vary how closely motion of the sprung mass follows motion of the unsprung mass.

Abstract: Disclosed herein are hydraulic actuators and methods for the operation of actuators having variable relative pressure ratios. Further disclosed are methods for designing and/or operating a hydraulic actuator such that the actuator exhibits a variable relative pressure ratio. In certain embodiments, the relative pressure ratio of the hydraulic actuator may be dependent on one or more characteristics (such as, for example, frequency or rate of change) of an oscillating input to the hydraulic actuator.

Abstract: Active suspension actuator systems including an actuator with a compression volume and an extension volume are described. In some embodiments, the system includes one or more flow control devices in fluid communication with the compression volume and/or the extension volume of the actuator. In some instances, a flow control device may include a pressure balanced blow-off valve (PBOV). In some embodiments, the system includes a high capacity bidirectional base valve. In some embodiments, two or more flow control devices cooperate to, for example, damp low amplitude oscillations in the extension and/or compression volumes, and to allow the build-up of pump generated differential pressures while discharging rapid road induced differential pressure spikes between the extension and compression volumes.

Abstract: Disclosed herein are hydraulic actuators and methods for the operation of actuators having variable relative pressure ratios. Further disclosed are methods for designing and/or operating a hydraulic actuator such that the actuator exhibits a variable relative pressure ratio. In certain embodiments, the relative pressure ratio of the hydraulic actuator may be dependent on one or more characteristics (such as, for example, frequency or rate of change) of an oscillating input to the hydraulic actuator.

Abstract: Disclosed herein are hydraulic actuators and methods for the operation of actuators having variable relative pressure ratios. Further disclosed are methods for designing and/or operating a hydraulic actuator such that the actuator exhibits a variable relative pressure ratio. In certain embodiments, the relative pressure ratio of the hydraulic actuator may be dependent on one or more characteristics (such as, for example, frequency or rate of change) of an oscillating input to the hydraulic actuator.

Abstract: Embodiments related to systems and methods for controlling the relative amounts of rotation and heave motions applied to a seat by an active seat suspension system are described.

Abstract: Presented herein are systems and methods for attenuating flow ripple generated by a hydraulic pump. In certain aspects, a method and system for operating a hydraulic positive displacement pump according to a stabilized command profile are disclosed, such that flow ripple generated by operation of the pump according to the stabilized command profile is attenuated as compared to operation of the pump according to a corresponding nominal command profile. In other aspects, a pressure-balanced active buffer is disclosed that allow for at least partially cancelling flow ripple in a hydraulic circuit comprising a pump. In another aspect, a method for generating ripple maps for a pump is disclosed. Such ripple maps may be used, for example, to determine the stabilized command profile used to operate the pump, or may be used by the pressure-balanced active buffer to counteract ripple in the hydraulic circuit.

Abstract: Presented herein are systems and methods for attenuating flow ripple generated by a hydraulic pump. In certain aspects, a method and system for operating a hydraulic positive displacement pump according to a stabilized command profile are disclosed, such that flow ripple generated by operation of the pump according to the stabilized command profile is attenuated as compared to operation of the pump according to a corresponding nominal command profile. In other aspects, a pressure-balanced active buffer is disclosed that allow for at least partially cancelling flow ripple in a hydraulic circuit comprising a pump. In another aspect, a method for generating ripple maps for a pump is disclosed. Such ripple maps may be used, for example, to determine the stabilized command profile used to operate the pump, or may be used by the pressure-balanced active buffer to counteract ripple in the hydraulic circuit.

Abstract: Disclosed herein are hydraulic actuators and methods for the operation of actuators having variable relative pressure ratios. Further disclosed are methods for designing and/or operating a hydraulic actuator such that the actuator exhibits a variable relative pressure ratio. In certain embodiments, the relative pressure ratio of the hydraulic actuator may be dependent on one or more characteristics (such as, for example, frequency or rate of change) of an oscillating input to the hydraulic actuator.

Abstract: At least one controller configured to control an actuator of an active suspension system. The at least one controller includes circuitry configured to determine an actuator state, and apply the actuator state and a commanded state to an inverse model of the actuator to produce an actuator command. The circuitry is configured to produce the actuator command by a process that includes performing low pass filtering and phase compensation to correct a phase introduced by the low pass filtering.

Abstract: A seat system for a vehicle includes a seat having a seat bottom on which a person can sit. An intermediate support structure is secured to the seat and the vehicle which allows the seat to rotate relative to the vehicle. An actuator can interact with the seat to cause the seat to rotate relative to the vehicle. The combined motion of the vehicle relative to the earth and the seat relative to the vehicle results in motion of the seat moving about a virtual pivot point. A user control is provided for adjustment of the location of the virtual pivot point.

Abstract: Disclosed herein are hydraulic actuators and methods for the operation of actuators having variable relative pressure ratios. Further disclosed are methods for designing and/or operating a hydraulic actuator such that the actuator exhibits a variable relative pressure ratio. In certain embodiments, the relative pressure ratio of the hydraulic actuator may be dependent on one or more characteristics (such as, for example, frequency or rate of change) of an oscillating input to the hydraulic actuator.

Abstract: An active suspension system that interfaces a sprung mass and an unsprung mass is disclosed. The active suspension system includes a suspension comprising one or more actuators capable of exerting a force on the sprung mass to at least partially isolate motion of the sprung mass from motion of the unsprung mass. A user interface allows a user to indicate a desired degree of motion isolation.

Abstract: An active suspension system for a sprung mass that is supported and movable relative to an unsprung mass. The active suspension system has a suspension that comprises an electromagnetic actuator that is adapted to produce an arbitrary force on the sprung mass that is independent of the position, velocity and acceleration of the sprung mass, a control system that provides control signals that cause the suspension to exert force on the sprung mass, to control the position of the sprung mass relative to the unsprung mass, wherein the control system implements a control algorithm with one or more constants, and a user interface that is operable to cause a change of one or more of the control algorithm constants so as to vary how closely motion of the sprung mass follows motion of the unsprung mass.